Renormalization Group Study of the Standard Model and its Extensions: II. the Minimal Supersymmetric Standard Model

In this paper we summarize the minimal supersymmetric standard model as well as the renormalization group equations of its parameters. We proceed to examine the feasability of the model when the breaking of supersymmetry is parametrized by the soft terms suggested by supergravity theories. In such models, the electroweak symmetry is exact at tree level and is broken spontaneously at one loop order. We make the additional assumption that the GUT-inspired relation $m_b=m_\tau$ be valid at the scale where the gauge coupling constants unify, which constrains the value of the top quark mass. For all types of soft breaking terms expected in supergravity theories, we present the results of numerical runs which yield electroweak breaking at the required scale. These yield not only the allowed ranges for the soft supersymmetry breaking parameters, but also the value of the supersymmetric partner' masses. For example in the strict no-scale model, in which global supersymmetry breaking arises solely from soft supersymmetry breaking parameters, but also the value of the supersymmetric partner' masses. For example in the strict no-scale model, in which global supersymmetry breaking arises solely from soft gaugino masses, we find that $M_t$ can be no heavier than $\sim 127$ GeV.Comment: 41 pages. ReVTeX typeset. 8 figures not included but available (as well as a full postscript version of the paper including the figures) by anonymous FTP at uful07.phys.ufl.edu in the het/UFIFT-HEP-93-18 directory. Report No. UFIFT-HEP-93-1

Lyrical Rapturing in Danticat’s Work: Transcending Haitian Cultural Silence through Narrative

Edwidge Danticat’s work has been praised for the visceral, deeply personal ways she writes violence, suffering, death, and loss, leading scholars to theorize that dehumanization is a central motif in the Haitian and Haitian diasporic experience. This causes Haiti to be generally considered, as Jerry Philogene describes, “a socially dead space”. Danticat ventures into this “socially dead space” in her recent memoirs, reflecting on the traumatic experiences of her two paternal figures, her father and Uncle Joseph, her complex feelings around her mother’s death, and the value of Haitian art in the aftermath of the 2010 earthquake. Danticat creates a language, I have coined as lyrical rapturing, that interrupts her narrative with prose that expresses her own residual pain from her personal traumas, triggering new processes of healing. This thesis will show how my theory of lyrical rapturing occurs in Danticat’s Brother, I’m Dying, The Art of Death, and Create Dangerously: the immigrant artist at work. By reflecting past works such as Breathe, Eyes, Memory, Danticat creatively theorizes the internalized process that helps her to continue to create despite the weight of such grief. Her lyrical rapturous language creates a blueprint of Haitians’ resilience and the cultural spirit that undergirds it, in the face of unfathomable devastation

An Autopsy of the Black Revolution: Looking at Henri Christophe through the Césairean lens

In his play The Tragedy of King Christophe, Aimé Césaire shows how Henri Christophe is incapable of establishing an anti-colonial black state because he adopts the colonial structure where his subjects are forced into free labor therefore perpetuating slavery. Instead of considering the immediate needs of the country, Christophe attempts to bring Haiti up as an equal competitor in the industrialized West despite its embargo and looming threat of reoccupation. Christophe becomes a slave master (the ultimate capitalist), thriving on the exploitation of his subjects to build the Citadel. This article looks at how Césaire\u27s play brings nuance to post-colonial discourse, showing how the initial victims of colonialism can perpetuate this framework if they profit from it.It also highlights the significance this piece of Haitian Revolutionary literature has on global black liberation literary movement. While the play goes beyond the accuracy of true historical events, Césaire contextualizes what dismantling colonialism potentially means

Structure, Organization, and Expression of the lct Gene for Lacticin 481, a Novel Lantibiotic Produced by Lactococcus lactis

The structural gene for the lactococcal lantibiotic lacticin 481 (lct) has been identified and cloned using a degenerated 20-mer DNA oligonucleotide based on the amino-terminal 7 amino acid residues of the purified protein. The transcription of the lct gene was analyzed, and its promoter was mapped. DNA sequence analysis of the lct gene revealed an open reading frame encoding a peptide of 51 amino acids. Comparison of its deduced amino acid sequence with the amino-terminal sequence and the amino acid composition of lacticin 481 indicates that the 61-residue peptide is prelacticin 481, containing a 27-residue carboxyl-terminal propeptide and a 24-residue amino-terminal leader peptide which lacks the properties of a typical signal sequence and which is significantly different from the leaders of other lantibiotics. The predicted amino acid sequence of prolacticin 481 contains 3 cysteines, 2 serines, and 2 threonines which were not detectable in amino acid analyses of mature lacticin 481. Based on these results and on characterization by two-dimensional NMR techniques, a structural model is proposed in which 2 cysteine residues are involved in lanthionine and one in β-methyllanthionine formation, and a 4th threonine residue is dehydrated. This model predicts a molecular mass for lacticin 481 of 2,901, which is in excellent agreement with that obtained from mass spectrometry.

DEVELOPMENT OF AN ENDOTHELIAL CELL/MESENCHYMAL STEM CELL COCULTURE STRATEGY FOR THE VASCULARIZATION OF ENGINEERED BONE TISSUE.

In the past two decades, remarkable progress has been made in the development of surgical techniques for bone reconstruction, significantly improving clinical outcomes. However, major reconstruction after trauma or cancer is still limited by the paucity of autologous material and donor site morbidity. Recent advances in the field of tissue engineering have generated new approaches for restoring bone defects. In spite of this progress, the necessity of suitable blood supply to ensure cell function is a major challenge in the development of more complex and functional grafts. Many investigators have successfully demonstrated the use of different strategies including growth factor delivery and in vitro coculture of ECs and MSCs to develop vascular structures. MSCs have the ability to secrete a wide range of bioactive cytokines and growth factors that can influence nearby cells via paracrine signaling. This crosstalk between ECs and MSCs is mutually beneficial, as ECs enhance osteogenic differentiation of hMSCs through direct cell-cell contact and paracrine signaling. In the native environment of cortical bone, both cell populations, osteogenic and vasculogenic, follow a unique well-defined pattern, called osteons. The goal of this proposed study was to develop a novel bio-inspired and vascularized bone construct, harvesting the synergistic effects of pro-angiogenic growth factor delivery and coculture of ECs and MSCs. To address this goal, we first developed mesoporous calcium deficient hydroxyapatite apatite microparticles, with biological properties closer to bone than commercially available hydroxyapatite, and capable of efficiently loading and sustainably releasing pro-angiogenic growth factors. We then demonstrated the successful fabrication of a novel bio-inspired 3DP fibrin-PCL composite scaffold, with mechanical strength comparable to bone. The utilization of these scaffolds in constructing osteons for bone regeneration demonstrated the promising capacity of the construct to improve neovascularization. In light of these results, we hypothesized that cell placement or patterning could play a critical role in neovascularization. Which lead us to investigate the role of distance between cell populations, introduced via 3D printing, in ECs/MSCs crosstalk. Our results suggested that controlling the distance between ECs and MSCs in coculture, using 3D printing, could influence angiogenesis

Autoregulation of Nisin Biosynthesis in Lactococcus lactis by Signal Transduction

The post-translationally modified, antimicrobial peptide nisin is secreted by strains of Lactococcus lactis that contain the chromosomally located nisin biosynthetic gene cluster nisABTCIPRKFEG. When a 4-base pair deletion is introduced into the structural nisA gene (ΔnisA), transcription of ΔnisA is abolished. Transcription of the ΔnisA gene is restored by adding subinhibitory amounts of nisin, nisin mutants, or nisin analogs to the culture medium, but not by the unmodified precursor peptide or by several other antimicrobial peptides. Upon disruption of the nisK gene, which encodes a putative sensor protein that belongs to the class of two-component regulators, transcription of ΔnisA was no longer inducible by nisin. Fusion of a nisA promoter fragment to the promoterless reporter gene gusA resulted in expression of gusA in L. lactis NZ9800 (ΔnisA) only upon induction with nisin species. The expression level of gusA was directly related to the amount of inducer that was added extracellularly. These results provide insight into a new mechanism of autoregulation through signal transduction in prokaryotes and demonstrate that antimicrobial peptides can exert a second function as signaling molecules.

Why do results conflict regarding the prognostic value of the methylation status in colon cancers? the role of the preservation method

<p>Abstract</p> <p>Background</p> <p>In colorectal carcinoma, extensive gene promoter hypermethylation is called the CpG island methylator phenotype (CIMP). Explaining why studies on CIMP and survival yield conflicting results is essential. Most experiments to measure DNA methylation rely on the sodium bisulfite conversion of unmethylated cytosines into uracils. No study has evaluated the performance of bisulfite conversion and methylation levels from matched cryo-preserved and Formalin-Fixed Paraffin Embedded (FFPE) samples using pyrosequencing.</p> <p>Methods</p> <p>Couples of matched cryo-preserved and FFPE samples from 40 colon adenocarcinomas were analyzed. Rates of bisulfite conversion and levels of methylation of <it>LINE-1, MLH1 </it>and <it>MGMT </it>markers were measured.</p> <p>Results</p> <p>For the reproducibility of bisulfite conversion, the mean of bisulfite-to-bisulfite standard deviation (SD) was 1.3%. The mean of run-to-run SD of PCR/pyrosequencing was 0.9%. Of the 40 DNA couples, only 67.5%, 55.0%, and 57.5% of FFPE DNA were interpretable for <it>LINE-1, MLH1</it>, and <it>MGMT </it>markers, respectively, after the first analysis. On frozen samples the proportion of well converted samples was 95.0%, 97.4% and 87.2% respectively. For DNA showing a total bisulfite conversion, 8 couples (27.6%) for <it>LINE-1</it>, 4 couples (15.4%) for <it>MLH1 </it>and 8 couples (25.8%) for <it>MGMT </it>displayed significant differences in methylation levels.</p> <p>Conclusions</p> <p>Frozen samples gave reproducible results for bisulfite conversion and reliable methylation levels. FFPE samples gave unsatisfactory and non reproducible bisulfite conversions leading to random results for methylation levels. The use of FFPE collections to assess DNA methylation by bisulfite methods must not be recommended. This can partly explain the conflicting results on the prognosis of CIMP colon cancers.</p